Hat holder



FIG. 1 is a perspective view of the hat holder showing my new design, the broken line showing of a hat being for illustrative purposes only and forming no part of the claimed design;

FIG. 2 is a bottom view thereof;

FIG. 3 is a top view thereof;

FIG. 4 is a front view thereof;

FIG. 5 is a back view thereof;

FIG. 6 is a left side view thereof; and,

FIG. 7 is a right side view thereof. 

The ornamental design for a hat holder, as shown and described. 